I imagened this to be similar to the guidance provided in the default P3D.
However, when selected, I've never seen any sign of it. Is it one of those things that has been dispensed with but never uninstalled?
If P3D's guidance is like FSX's, these are lines/arrows on the ground.
PF3 does not have those (as it has no code to render pixels in the flight sim world), but (apart from the HDG bug or voice guidance) offers the following two ways to get a visual guidance:
1. Via the TGS gauge: You need to edit your aircraft's panel.cfg as described in section 22 of the user manual. I'm not sure if this is compatible with P3D though.
2. Via the standalone TGS Display, as show in section 8.2. This is a separate program you need to start outside of P3D.